Enough should be committed to show a business ready to operate and capital genuinely at risk, which usually means key contracts signed and key spending done. How much further to commit before an outcome is known is a business risk decision. No processing time, appointment date or approval can be promised.
Stage commitments against decision points
One workable sequence: settle the manufacturing terms, secure workspace, place the first production order, hire or contract initial sales capacity, then finalize the case. Where a commitment would be ruinous if the plan changed, discuss with counsel whether it can be staged or conditioned. Plan also for the difference between a visa's validity and the stay authorized at admission, and for departure when status ends.
Set milestones: amended terms signed, payment released from escrow, delivery schedule confirmed, evidence pack reviewed. Fix dates for due diligence, the funding trail, signed lease and supplier terms, and the reviewer's assessment of non-marginality. An escrow whose only outstanding condition is issuance of the visa is accepted in official guidance as a solid, irrevocable commitment, while one the buyer can unwind for reasons of their own has preserved the funds rather than committed them.
Set dates for the segment rebuild, the adviser's review, and the final packet, then treat government steps as outside your control: no processing time or outcome can be guaranteed.