How much would i be earning of a 6-card 1050ti rig or should i stay with 6 750ti’s?

Roughly $7.77 per day mining zcash before accounting for electrical costs…

x6 1050ti will give you 1080 Sol/s about 8 $ per day at the current price, while while x6 750ti 450 Sol/s. But this web calculates at the best possible performance and not default for all. you will have to tweak it and see which miner works best for you.

https://whattomine.com/coins?utf8=✓&adapt_q_280x=0&adapt_q_380=0&adapt_q_fury=0&adapt_q_470=0&adapt_q_480=0&adapt_q_570=0&adapt_q_580=0&adapt_q_vega56=0&adapt_q_vega64=0&adapt_q_750Ti=0&adapt_q_1050Ti=6&adapt_1050Ti=true&adapt_q_10606=0&adapt_q_1070=0&adapt_q_1080=0&adapt_q_1080Ti=0&factor[eth_hr]=83.4&factor[eth_p]=420.0&grof=true&factor[gro_hr]=87.0&factor[gro_p]=450.0&factor[x11g_hr]=29.4&factor[x11g_p]=450.0&cn=true&factor[cn_hr]=1800.0&factor[cn_p]=300.0&eq=true&factor[eq_hr]=1080.0&factor[eq_p]=450.0&lre=true&factor[lrev2_hr]=87000.0&factor[lrev2_p]=450.0&factor[ns_hr]=2520.0&factor[ns_p]=450.0&factor[lbry_hr]=660.0&factor[lbry_p]=450.0&factor[bk2b_hr]=4200.0&factor[bk2b_p]=450.0&factor[bk14_hr]=6300.0&factor[bk14_p]=450.0&factor[pas_hr]=2280.0&factor[pas_p]=450.0&factor[skh_hr]=69.0&factor[skh_p]=450.0&factor[l2z_hr]=420.0&factor[l2z_p]=300.0&factor[cost]=0.1&sort=Profitability24&volume=0&revenue=24h&factor[exchanges][]=&factor[exchanges][]=abucoins&factor[exchanges][]=bitfinex&factor[exchanges][]=bittrex&factor[exchanges][]=bleutrade&factor[exchanges][]=cryptopia&factor[exchanges][]=hitbtc&factor[exchanges][]=poloniex&factor[exchanges][]=yobit&dataset=&commit=Calculate

another alternative the 1050ti will provide is etherium although not so good but with the 750ti you cant mine etherium.