Before you think about balancing you should consider what you have to work with. In fact on a low flop like this your value checkraise range is pretty small. If you checkraise, your range will be very small no matter what, even if you balance your value raises with some bluffs. When your checkraise range is only a small part of your total range then the impact of any hands you balance your range with has to be even smaller. It might well be not worth it to give away a lot of information when your gain could only be minimal.
Consider this:
Board: 7♠4♥2♦
Equity Win Tie
MP2 46.41% 46.41% 0.00% { 66 }
MP3 53.59% 53.59% 0.00% { 77+, ATs+, KQs, AJo+ }
Board: 7♠4♥2♦
Equity Win Tie
MP2 55.28% 54.89% 0.39% { A7s }
MP3 44.72% 44.34% 0.39% { 77+, ATs+, KQs, AJo+ }
Board: 7♠4♥2♦
Equity Win Tie
MP2 51.92% 51.40% 0.52% { 99 }
MP3 48.08% 47.56% 0.52% { 77+, ATs+, KQs, AJo+ }
Basically your value range begins with 99+, A7+. Depending on whether you cap anything preflop or whether you play a no cap strategy the number of your value hands is between 12 and 42 out of a total range of 171 hands. That's really a small part of your range. When you checkraise 12/171 = 7% of your range for value and add maybe another 3 bluffs for balancing your balancing range counts for less than 2% of your total range.
Add in the fact that you will have absolutely no fold equity on the flop and have to always follow up on the turn and it becomes clear that this probably isn't worth it.
So, what are the alternatives? The alternative is to check/call any hand you want to play on the flop. It is also balanced because you will not call a hand which has too little equity. You don't have to be afraid that you lose value because it is very likely that the opponent will follow up with another bet on the turn and you can exploit that. If you have a read that he doesn't bet the turn always that's not a tragedy because then you can call any hand on the flop for the possiblity of a free card on the turn. As your value range is small, a really big part of your range would profit.
QJo is near the lower bound of your Range. Your pot odds are 7,5:1, so will need 5,5 outs to call. QJo might not have it but you will have implied odds if you hit your pair on the turn. The opponent will usually bet the turn with nearly 100% of his range on the turn because cc flop doesn't represent a strong range (and he is right about it). If you hit a J on the turn your equity will be north of 60%.
Board: 7♠4♥2♦ J♠
Equity Win Tie
MP2 62.41% 62.41% 0.00% { QdJh }
MP3 37.59% 37.59% 0.00% { 77+, ATs+, KQs, AJo+ }
You can add at least 0,5 BB implied odds for turn and river, which is another 1 SB on the flop. Therefore your total odds on the flop would be no less than 8,5:1.
I think you will need somewhere around 4,5 outs for a call on the flop or a little more. QJ has like 3,5 outs. 3 outs have 12,5% equity while 4 outs have 16,5% equity.
Board: 7♠4♥2♦
Equity Win Tie
MP2 14.46% 14.46% 0.00% { QdJh }
MP3 85.54% 85.54% 0.00% { 77+, ATs+, KQs, AJo+ }
On the turn another card will come that your range can hit. That means usually your value range on the turn will be greater than on the flop. If you delay your play to the turn you will have more to work with.
There may be also a misconception about balanced folding (or GTO folding). Folding the bottom x% of your range as a GTO play only applies if you have no outs and every single hand in your folding range has showdown equity. For hands that don't have any showdown value and that don't have outs this does not apply.
Examples:
Imagine the opponent has a range which has 100% of your range beat on the river. It is then absolutely correct to fold 100% of your range no matter how the pot odds are.
Imagine you have a range where the opponents range has you 100% beat but every single hand of your range has enough outs to call. It would be incorrect to fold anything.
On the flop you usually have outs against at least some part of the range of the opponent while there may be also hands that have showdown value and hands that have no value whatsoever. Folding the no value hands can be absolutely correct even if this is more than the 1/odds+1 part of your range. When you look for balance you can still balance the other part of your range.