Starting with 5th gen. During initial stage of fgfa, IAF planned to buy 250 jets which reduced to 144 plus prototype and AMCA going to replace Mig29, Mirage 2000 and some jags means around 200 and combine both gets 344 plus, means IAF need around 350 Fifth gen, and I'm considering around 300.
4th gen, all 4th gen including early Su 30 starts retiring from 2035 onwards when AMCA mk2 arrives. Means IAF need 150 lca mk2. Mk1a help to keep sqn strength, but uses USA engine and same case with mk2, mki having heavy maintenance, low sortie rate. two pilots, extra makes IAF to reduce its sqn strength, makes room for AMCA. 100 LCA helps IAF to keep current sqn strength, MMRCA helps to fill mig23/mig27 with mki and increase sortie rate, mk2 helps to fill mig 29 and jaguar fleet, AMCA fill mki, mirage fleet and 6th gen replace mk1 and goes on, with job shared by ucav. The no.of lca mk2 depends on AMCA success and total no.of MMRCA brought. We are going to spend huge money into AMCA even its engine require multi billions r&d, buying just 150 nos doesn't make any sense, around 250 plus is a good number also IAF demanded indigenous engine not a US one, giving huge potential of AMCA vs lca mk1a. lca mk2 mwf[vs mki]. <42 sqn is the target>